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AOSC Seminar
April 4, 2019

Horizontal Convective Rolls: An Underappreciated Circulation?

David Stensrud
The Pennsylvania State University

Horizontal convective rolls (HCRs) are commonly observed as regularly-spaced lines of cloud bands, or streets, over the coastal waters when cold air flows across warm water.  Cloud streets also are observed over land, although less often.  Cursory inspection of WSR-88D clear-air observations, however, suggests that HCRs are a fairly common occurrence over land.  HCRs are important as they act to mix the boundary layer and are known to be associated with the initiation of deep convection.  The mechanisms leading to the formation of HCRs will be summarized, and a look at the monthly frequency of HCR formation in central Oklahoma will be explored for two years.  The goal of this project is to develop a 10-year climatology of HCRs in central Oklahoma to provide a baseline for a comparison with HCRs produced by numerical weather prediction models.   The value of serendipity will also be discussed.